$ ag "preg_split\(([^'\)]*|('.*')),([^'\)]*|('.*'))," | grep null
question/type/gapselect/questiontypebase.php:185:                null, PREG_SPLIT_DELIM_CAPTURE);
question/type/multianswer/questiontype.php:284:                null, PREG_SPLIT_DELIM_CAPTURE);
lib/form/classes/filetypes_util.php:71:            $types = preg_split('/[\s,;:"\']+/', $types, null, PREG_SPLIT_NO_EMPTY);
lib/tests/messageinbound_test.php:108:                null, PREG_SPLIT_DELIM_CAPTURE);
lib/php-css-parser/Parsing/ParserState.php:285:				return preg_split('//u', $sString, null, PREG_SPLIT_NO_EMPTY);
mod/workshop/locallib.php:451:            $extensions = preg_split('/[\s,;:"\']+/', $extensions, null, PREG_SPLIT_NO_EMPTY);